Follicular Unit Extraction (“FUE”) is a surgical hair transplantation technique that involves moving skin containing hair follicles from one part of the body (the donor site) to bald or balding parts (the recipient site). Hair naturally grows in follicles that contain groupings of 1 to 4 hairs, and the transplant technique typically moves the 1-4 hair “follicular units” from the donor site to the recipient site.
The follicle units (sometimes referred to as “grafts”) are typically removed from the donor site using punches of between 0.7 mm and 1.25 mm in diameter. The punches are typically tubular bodies having a skin-contacting cutting edge, and are typically mounted in a hand-held electric-powered tool that causes the punch to rotate or oscillate as the cutting device is brought into contact with the donor site, but are sometimes used manually.
Hair follicles are very easily broken during the removal, and broken follicles are unlikely to be successfully transplanted. One of the major causes of low yield in FUE is attributable to desiccation forces imparted on the graft following its dissection from its tissue investiture; more specifically, as it is pulled from the donor site, and as it is placed in a physiological holding solution such as normal saline, ringer's lactate, etc. for subsequent transplantation at the recipient site.
One known FUE device even uses a suction mechanism to suck out the graft immediately following desiccation and propel it pneumatically through a tube into a collection canister that contains a physiological medium. The sucked graft is subjected to traumatic forces as it is funneled at high force and velocity out of the donor site and through the narrow tube, banging against the tube wall as it is propelled to the canister. Additionally, sucking and pulling the graft as it is cut from the donor site creates a risk of transection from the combined vectors of pulling and rotating as the rotating cutting device creates a like rotation in the graft being extracted while it is tethered to the surrounding tissue at the donor site. Moreover, the suction effect strips the graft of some of its protective tissue investiture, further diminishing its protection from damaging desiccating factors as well as trauma.